docs: def add_value_option(self, *args, **kwargs):
          """ Add a value option.
  
              @keyword dest: Destination attribute, derived from long option name if not given.
              @keyword action: How to handle the option.
              @keyword help: Option description.
              @keyword default: If given, add this value to the help string.
          """
          kwargs['metavar'] = args[-1]
          if 'dest' not in kwargs:
              kwargs['dest'] = [o for o in args if o.startswith("--")][0].replace("--", "").replace("-", "_")
          if 'default' in kwargs and kwargs['default']:
              kwargs['help'] += " [%s]" % kwargs['default']
          self.parser.add_option(*args[:-1], **kwargs)